Q.

The de Broglie wavelength of a molecule in a gas at room temperature (300 K) is λ1. If the temperature of the gas is increased to 600 K, then the de Broglie wavelength of the same gas molecule becomes                  [2023]

1 12 λ1  
2 2λ1  
3 12 λ1  
4 2 λ1  

Ans.

(1)

From K.T.G

vRMS=3kBTm

vRMS∝T  and  hmvRMS=λ ⇒ λ∝1T

λ2λ1=T1T2=300600=12

⇒  λ2=λ12